[Chesapeake Quarterly masthead]
Volume 1, Number 3
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Summary of Field Trial
C. ariakensis vs. C. virginica

In a study of survival, growth and disease susceptibility of both oysters, VIMS scientists compared triploid (i.e., sterile) C. ariakensis with diploid (fertile) C. virginica at sites in three different salinity regimes: low (less than 15 ppt), medium (15-25 ppt) and high (greater than 25 ppt) in the Chesapeake Bay and on the Atlantic coast. The medium and high sites were conducive to MSX and Dermo disease. The results, shown below, demonstrate that C. ariakensis grew remarkably well. Researchers note, though, that C. virginica were at a disadvantage in that they were not only diploid animals, but were already infected with Dermo when tests were conducted.


  • C. ariakensis: Low salinity sites, 14% mortality; at medium and high salinity sites, 15%
  • C. virginica: Low salinity sites, 81% mortality; at medium and high salinity sites, 100%

Growth after One Year at Low, Medium and High Salinity

  • C. ariakensis: Mean length, 96 mm (low), 125 mm (medium), 140 mm (high)
  • C. virginica: Mean length, 72 mm (low), 85 mm (medium), 75 mm (high)

Disease Prevalence during Second Summer

  • C. ariakensis: 0-28% infected at three sites, mostly light infections
  • C. virginica: 100% infected at all sites, heavy infections

Adapted from Calvo, G.W., M.W. Luckenbach, S.K. Allen, Jr., and E.M. Burreson. 2000. A Comparative Field Study of Crassostrea ariakensis and Crassostrea virginica in Relation to Salinity in Virginia. Special Report in Applied Marine Science and Ocean Engineering No. 360. Virginia Institute of Marine Science.

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